Wenger laments lack of confidence
With just two wins in eight Premier League matches, Wenger's men are seventh and already 11 points behind leaders Chelsea.
Wenger, whose side visit Sunderland on Saturday, is frustrated but cannot fault the attitude of his squad or their quality.
"I think 95 per cent is there. It is normal that after a World Cup, and we have new players, you see the main thing is there – the attitude, the quality," he said.
"But the water boils at 100 degrees and not at 99, and we have to add that degree.
"It is frustrating but we have to play better. That is how we have to think. We dominate our games.
"It is just when we have a weaker moment we pay for it. That is why I think we have to produce more effort defensively as a team.
"We could be more efficient offensively and defensively but that will come. I can understand that better because there are players who are new.
"I think we are never in positions where we have the lead for a long time, we are always chasing back. Of course that makes it more difficult offensively.
"We have to win at Sunderland. I cannot deny that. I believe it is linked with confidence at the moment but I cannot fault the attitude."
Wenger is unfazed by Chelsea's start to the campaign, despite Jose Mourinho's men being five points clear of nearest rivals Manchester City.
The Frenchman said his focus was on Arsenal and no-one else.
"That [Manchester United beating Chelsea] doesn't help us if we don't produce the performances," Wenger said.
"We don't produce the results at the moment. We have not to look at Chelsea, we have to look at ourselves and just get the results.
"I look at how we can be more efficient. That's my only worry."